COUNT

Returns the number of rows matching the query criteria.

SELECT COUNT(*) FROM Customers WHERE Column2 = 'Bob'

COUNT(DISTINCT)

Returns the number of distinct, non-null field values matching the query criteria.

SELECT COUNT(DISTINCT FirstName) AS DistinctValues FROM Customers WHERE Column2 = 'Bob'

AVG

Returns the average of the column values.

SELECT LastName, AVG(AnnualRevenue) FROM Customers WHERE Column2 = 'Bob'  GROUP BY LastName

MIN

Returns the minimum column value.

SELECT MIN(AnnualRevenue), LastName FROM Customers WHERE Column2 = 'Bob' GROUP BY LastName

MAX

Returns the maximum column value.

SELECT LastName, MAX(AnnualRevenue) FROM Customers WHERE Column2 = 'Bob' GROUP BY LastName

SUM

Returns the total sum of the column values.

SELECT SUM(AnnualRevenue) FROM Customers WHERE Column2 = 'Bob'